Systems involving fiber optic igniters

ABSTRACT

A gas turbine engine system comprising, a gas turbine engine including a combustion area, a laser, a fuel nozzle including a cavity operative to transmit a fuel into the combustion area, and an optical fiber engaging the cavity, operative to transmit light emitted from the laser to the combustion area, wherein the light is operative to ignite the fuel in the combustion area.

BACKGROUND OF THE INVENTION

The present disclosure relates generally to systems involving ignitingfuel, and more particularly to systems involving igniting fuel withlight from a fiber optic system.

Engines that use combustible fuel such as, for example, gas turbineengines and internal combustion engines include combustion areas suchas, for example, combustors or cylinder and piston assemblies thatfacilitate the conversion of energy from combustion into mechanicalenergy. Fuel nozzles are used to introduce atomized fuel into thecombustion areas. The atomized fuel is ignited by an igniter. Ignitersmay include, for example, electrical igniters that create a sparkproximate to the atomized fuel, heating elements that introduce heat tothe atomized fuel, and igniters that introduce a flame in the combustionarea.

For turbine applications, igniters are typically based on electricaldischarge. Electrical discharge igniters need much more space inside thecombustion chamber. The electrodes cannot be placed inside the cone ofthe fuel spray since the droplets would lead to strong deposits on theelectrodes and thus reduce the durability of the igniter. High sparkenergies, which are needed for successful ignition, also significantlyreduce the lifetime of the igniter.

Accordingly, there is a need for improved igniters where space islimited such as may be the case with turbine applications.

BRIEF DESCRIPTION OF THE INVENTION

An exemplary embodiment includes a gas turbine engine system comprising,a gas turbine engine including a combustion area, a laser, a fuel nozzleincluding a cavity operative to transmit a fuel into the combustionarea, and an optical fiber engaging the cavity, operative to transmitlight emitted from the laser to the combustion area, wherein the lightis operative to ignite the fuel in the combustion area.

An alternate exemplary embodiment includes a system for ignitingcombustible fuel comprising, a laser, and an optical fiber partiallydefining a first channel and a second channel, wherein the first channelis operative to transmit light emitted from the laser to a combustionarea, and the second channel is communicative with a fuel source and thecombustion area and is operative to introduce fuel from the fuel sourceinto the combustion area.

Another alternate exemplary embodiment includes a system for ignitingcombustible fuel comprising, a laser, and an optical fiber partiallydefining a channel communicative with a fuel source and a combustionarea and operative to introduce fuel from the fuel source into thecombustion area, wherein the channel is further operative to transmitlight emitted from the laser to the combustion area and the light isoperative to ignite the fuel.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages will become betterunderstood when the following detailed description is read withreference to the accompanying drawings in which like charactersrepresent like parts throughout the drawings, wherein:

FIG. 1 illustrates of an exemplary embodiment of a system for ignitingcombustible fuel.

FIG. 2 illustrates of an exemplary portion of light from the system ofFIG. 1.

FIGS. 3-7 illustrate alternate exemplary embodiments of the system forigniting combustible fuel.

FIG. 8 illustrates another alternate exemplary embodiment of the systemfor igniting combustible fuel including a gas turbine engine.

FIG. 9 illustrates another alternate exemplary embodiment of the systemfor igniting combustible fuel including an internal combustion engine.

DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description, numerous specific details are setforth in order to provide a thorough understanding of variousembodiments. However, the embodiments may be practiced without thesespecific details. In other instances, well known methods, procedures,and components have not been described in detail.

Further, various operations may be described as multiple discrete stepsperformed in a manner that is helpful for understanding the embodiments.However, the order of description should not be construed as to implythat these operations need be performed in the order they are presented,or that they are even order dependent. Moreover, repeated usage of thephrase “in an embodiment” does not necessarily refer to the sameembodiment, although it may. Lastly, the terms “comprising,”“including,” “having,” and the like, as used in the present application,are intended to be synonymous unless otherwise indicated.

In one embodiment, laser light is used to create heat in a fuel, or maybe focused to create a micro-spark so as to initiate the combustion offuel in a combustion area.

FIG. 1 illustrates a diagram of an optical fuel igniter system 100. Theoptical fuel igniter system 100 includes a laser source 101 in opticalcommunication with one end of an optical fiber 103. The other end of theoptical fiber is in optical communication with a fuel. Generally, thefuel is injected into a combustion area by means of fuel nozzle 105. Thelaser source is configured to generate light at a wavelength and powereffective to be absorbed by the fuel and ignite the fuel, oralternatively, cause a microspark within the fuel to occur. The laserlight is focused at about an area within a combustion area 107 where thefuel will flow. The fuel is not intended to be limited to any particulartype or kind so long s it is combustible. For example, the fuel can be agas or liquid,

In operation, the fuel nozzle 105 receives fuel from a fuel source (notshown) and emits the fuel into a combustion area 107. The fuel may beemitted as atomized fuel 109 such that the fuel may be easily combusted.The laser 101 emits a light 111 that is transmitted by the optical fiber103. When the light 111 enters the atomized fuel 109, the atomized fuel109 combusts. FIG. 2 illustrates two examples of the interaction of thelight 111 with the atomized fuel 109 that may cause the atomized fuel tocombust. FIG. 2 includes fuel droplets 201 and light 111. The light 111may be absorbed by the fuel droplets 201 causing the temperature of thefuel droplets 201 to increase. If the increase in the temperature of thefuel droplets 201 reaches an ignition temperature of the fuel droplets201, the droplets will combust. Another cause of combustion may be amicro-spark. As the light 111 passes through a fuel droplet 201, it maybecome focused such that a micro-spark 203 results. The micro-spark maycause the fuel droplets 201 to combust. Optics (not shown) that include,for example a lens, or a number of lenses may also be used to focus thelight 111 and create the micro-spark 203. Examples of lasers that may beused for the laser 101 include, but are not limited to Neodymium-typelasers, Erbium-type lasers or any other solid state lasers.Semiconductor lasers may also be used as for the laser 101.

FIG. 3 illustrates an alternate embodiment of an optical fuel ignitersystem 300. The optical fuel igniter system 300 is similar to theoptical fuel igniter system 100 of FIG. 1, however optical fuel ignitersystem 300 includes an optical fiber 303 that has an distal portion 313that has a convex shape. The convex shape of the distal portion 313focuses the light 111 causing a micro-spark 203 in the atomized fuel109.

FIG. 4 illustrates an alternate embodiment of an optical fuel ignitersystem 400. The an optical fuel igniter system 400 is similar to the anoptical fuel igniter system 100, and includes an optics portion 415comprising, for example, a lenses, a number of lenses, or similardevices that focus light. The optics portion 415 is disposed between theoptical fiber 103 and the combustion area 107. The optics portion 415focuses light emitted from the optical fiber such that a micro-spark 203is created in the atomized fuel 109.

FIG. 5 illustrates an alternate exemplary embodiment of an optical fueligniter system 500. In the illustrated embodiment a fuel nozzle 505includes a cavity 519. The cavity 519 is engaged by the optical fiber103. In operation, the fuel nozzle receives fuel from a fuel source 517,and emits the fuel into the combustion area 107 via the cavity 519. Theoptical fiber 103 transmits light 111 from the laser 101 into thecombustion area 107 to ignite the atomized fuel 109 in the combustionarea 107. The optical fiber 103 may also be convex shaped similar to thetip 313 of FIG. 3. In some embodiments, the optics portion 415 may alsobe disposed in the path of the light 111 to focus the light 111.

FIG. 6 illustrates an alternate embodiment of an optical fuel ignitersystem 600. The illustrated embodiment includes the laser 101, theoptics 415, the fuel source 517, the combustion area 107, an end member627, and an optical fiber 625 having a first channel 623 and a secondchannel 621. The optical fiber 625 may be, for example, a photoniccrystal fiber, or other types of optical fibers that have a number ofchannels. The end member is disposed on an end of the optical fiber 625.In operation, fuel is received from the fuel source 517 and emitted intothe combustion area 107 as atomized fuel 109 via the second channel 621.The laser 101 emits light 111 that may be focused with the optics 415such that the light 111 causes the atomized fuel 109 to combust. Theillustrated embodiment shows a single second channel 621, however otherembodiment may include a plurality of channels similar to the secondchannel 621 that may carry fuel from the fuel source 517 to thecombustion area 107. The end member 627 may be transparent orsemitransparent. The end member 627 seals the first channel 623 and thesecond channel 621 such that fuel flows towards the combustion area 107.The optical fiber 103 may also be convex shaped similar to the tip 313of FIG. 3. In some embodiments, the optics portion 415 may also bedisposed in the path of the light 111 to focus the light 111.

FIG. 7 illustrates an alternate embodiment of an optical fuel ignitersystem 700. The optical fuel igniter system 700 includes a hollow corefiber 727 having a channel 729. The hollow core fiber 727 may be, forexample, a fiber having a channel with a high reflection coating on thesurface of the channel 729 and hollow core photonic crystal fibers. Inoperation, fuel 731 from the fuel source 517 enters the channel 729.Light 111 enters the channel 729 after it has been focused by the optics415. In alternate embodiments, and the light 111 may enter the channel729 without the optics 415 disposed between the laser 101 and the hollowcore fiber 727. The focused light 111 in the channel 729 causes themicro-spark 203 in the channel 729. The micro-spark 203 ignites the fuel731 in the channel 729, causing a flame (not shown) to exit the channel729 and ignite atomized fuel in the combustion area 107. The opticalfiber 103 may also be convex shaped similar to the tip 313 of FIG. 3. Insome embodiments, the optics portion 415 may also be disposed in thepath of the light 111 to focus the light 111.

FIG. 8 illustrates a side partially cut-away view of an exemplaryembodiment of a gas turbine engine system 800 that includes a combustorsection 801 that partially defines the combustion area 107. An opticalfuel igniter system 802 including the fuel nozzle 105, the laser 101,and the optical fiber 103 may be similar to any of the embodiments ofthe optical fuel igniter system described above. The gas turbine enginesystem 800 also includes a controller 809 that is operative to controlthe optical fuel igniter system 802

In some embodiments components of the optical fuel igniter system 802may be located in a remote location from the gas turbine engine such as,for example, the controller 809 and the laser 101 may be located in anintegrated electronic control unit (not shown).

In operation, compressed air enters the combustion area 107 and is mixedwith fuel from the fuel nozzle 105. The fuel-air mixture is ignited bylight from the laser 101 via the optical fiber 103 as described in theembodiments above. The resultant expanding gas exits the combustion area107 and is converted into mechanical power.

FIGS. 1-7 illustrate embodiments of a fuel nozzle that may, for example,be used as a main fuel nozzle for the combustion area 107.Alternatively, the embodiments described above may be used as pilotnozzles that are operative to ignite fuel in the combustion area 107. Ifused as a pilot nozzle, the embodiments may, for example, receive fuelfrom a separate fuel supply line that services the pilot nozzle.

FIG. 9 illustrates a side partially cut-away view of an exemplaryembodiment of an internal combustion engine system 900 that includes anoptical fuel igniter system having the combustion area 107, the fuelnozzle 105, the laser 101, and the optical fiber 103. The internalcombustion engine system 900 may be similar to any of the embodiments ofthe optical fuel igniter system described above.

This written description uses examples to disclose the embodiments,including the best mode, and also to enable practice of the embodiments,including making and using any devices or systems and performing anyincorporated methods. The patentable scope of the embodiments is definedby the claims, and may include other examples. Such other examples areintended to be within the scope of the claims if they have structuralelements that do not differ from the literal language of the claims, orif they include equivalent structural elements with insubstantialdifferences from the literal languages of the claims.

1. A gas turbine engine system comprising: a gas turbine engineincluding a combustion area; a laser; a fuel nozzle including a cavityoperative to transmit a fuel into the combustion area; and an opticalfiber engaging the cavity, operative to transmit light emitted from thelaser to the combustion area, wherein the light is operative to ignitethe fuel in the combustion area.
 2. The system of claim 1, wherein theoptical fiber includes a distal portion operative to focus the light inthe combustion area.
 3. The system of claim 2, wherein the distalportion is convex shaped.
 4. The system of claim 1, wherein the systemfurther comprises an optics portion operative to focus the light in thecombustion area.
 5. A system for igniting combustible fuel comprising: alaser; and an optical fiber partially defining a first channel and asecond channel, wherein the first channel is operative to transmit lightemitted from the laser to a combustion area, and the second channel iscommunicative with a fuel source and the combustion area and isoperative to introduce fuel from the fuel source into the combustionarea.
 6. The system of claim 5, wherein the system further comprises anend member disposed on a distal portion of the optical fiber proximateto the laser.
 7. The system of claim 5, wherein the system furthercomprises an optics portion disposed between the laser and the opticalfiber, the optics portion operative to focus the light.
 8. The system ofclaim 5, wherein the system optical fiber comprises a photonic crystal.9. The system of claim 5, wherein the system further comprises a gasturbine engine.
 10. The system of claim 5, wherein the system furthercomprises an internal combustion engine.
 11. A system for ignitingcombustible fuel comprising: a laser; and an optical fiber partiallydefining a channel communicative with a fuel source and a combustionarea and operative to introduce fuel from the fuel source into thecombustion area, wherein the channel is further operative to transmitlight emitted from the laser to the combustion area and the light isoperative to ignite the fuel.
 12. The system of claim 11, wherein thesystem further comprises an end member disposed on a distal portion ofthe optical fiber proximate to the laser.
 13. The system of claim 11,wherein the system further comprises an optics portion disposed betweenthe laser and the optical fiber, the optics portion operative to focusthe light.
 14. The system of claim 11, wherein the light is operative toignite fuel in the channel.
 15. The system of claim 11, wherein thelight is operative to ignite fuel in the combustion area.
 16. The systemof claim 11, wherein the system further comprises a gas turbine engine.